Method and apparatus for forming cores



Aug. 31, 1943 E. A. PETERSEN 2,323,357

ETHOD AND APPARATUS FOR FORMING CORES Filed Jan. 26, 1942 3 Sheets-Sheet1 INVENTOR 5 6215621.

A T T ORNE Y6.

Aug; 31, 1943. E.A. PETERSEN METHOD AND APPARATUS FOR FORMING CORESFiled Jan. 26, 1942 3 Sheets-Sheet 2 INVENTOR 1 m A TTORNEYS.

1943- E. A. PETERSEN 2,328,357

v METHOD AND APPARATUS FOR FORMING CORES Filed Jan. 26, 1942 3Sheets-Sheet 3 A l J6 amf;

INVENTOR I r I I I I I l ATTORNEYS- I UNITED Patented Aug. 31, 1943METHOD AND STATES PATENT OFFICE srmnarnsnonronmmoooms .Edgar A.Petersen, Grosse Pointe, Mich, assignor to Chrysler Corporation,Highland Park, Mich acorporation of Delaware Application January as,1942, SerialNo. 428.182 w sand under pressure into a cavity of thecoreforming apparatus in a manner which facilitates relative separationor drawing of the molding 3 apparatus. a

A piston foryuse in an internal combustion engine llas reinforcing ribsonthe internal surface, such" ribs being provided for both the head and5 skirt portions of the piston. Formation of these ribs and the conventional'wrist pin bosses re- 'quiresa core-formingfapparatus which hastherein parts drawn transversely to the-core while other parts, such asthe rib-forming grooves in 'the core, necessitate adraw-in a directionaxially with respe'c'tto the core." 5 i i Itis advantageous in themaking of these cores to employ the sand blasting method rather thanhand packing andto so introduce the core-forming sand into themoldingcavity that the same .10 of sand cores by introducing the core-forming 1will not become lodged or-wedged between parts of the apparatus as toprevent the'relative sepai ation ofjtheseparts with ease.

w Core making apparatus includes an open end andan axially oppositecovered end through which vanes or fingers extend. into the core moldingcavity for formin grooves in thecore, these grooves in turn forming thereinforcing ribs. When the core-formingsand was, admitted ,through the:printend under pressure it was found j that send lodged between thevanes and the slots l'nwh'ich' they were slidably received and after anumber of cores were .thus formed this; sand acted asa wedge andprevented these panama,

being relatively separatedf I have i found that by admitting sandthrough f the normally covered end, opposite the print. end, theaforesaid difficulties have been overcome and that relative separationof the vanes or fingers from the cavity is made with ease, the wedgingaction of the same being no longer present.

squeezing operation by inserting as'uitable tool it through theblowopening in the covered end to imprint the adjacent endface ofthecore withcore forming apparatus.

Referring to Figs. 1,2 and 3, 4

designates a piston for an internal combustion engine The piston hasring-receivinggrooves and apparatus, reference is made-to theaccompanying drawings in which: v Fig.1 is an elevational view, partly.in section, of a piston made according to the principles of theinvention- Fig1 2 is a sectional'view taken asindicated by I the line2+2 of Fig. 1.

Fig. 3 is an end view taken as indicatedby the line3-3of Fig. 1, w

Fig; 4 is artransverse section through a mold showing thecore locatedtherein for castingof thepiston. i

Fig; 5 is i a side elevational' View illustrating the.

Fig. 6 is a top plan. vie taken on line 5 6 of Fig.5. 1

Fig. 7 is a fragmentary section'taken on line 7lofFig;6.

Fig. 8 is a side elevational view, partly in section, taken on the line8-8 of Fig. 6. g

Fig. 9 isa sectional view taken on line 9--.- of Fig.5..

Fig. 10 is aside elevational view,partly in section; and similar'to Fig.5, with the groove forming vane beingremoved and'the imprinting toolshown in operatin'g position;

the numeral l 5 [6 in the headther eof and wrisflpin bosses l1.

The piston is reinforced by a plurality of ribs on theinner surfacethereof including the circumferential ribs I8 connecting the bosses l7,and

a plurality of axially extending ribs 19 which also appear onlthe innerfaceof the closed end 'ofthe piston and which intersect the annular rib20 onthe latter face. The end faceof the piston has a: centrallylocated;dep'ression at 2| for lathe centering during machiningjof thecasting, the thickness of the end being increased byan internal boss 22registering with the depression 2|. The core used infcastingflthe pistonl5 is outlined by the dash lines ihQFigs. 1" and 2.1

The core, generally designated by the' numeral u 23, used in casting thepiston islmore particularly '50 when the foregoing is practicedthere isadded a the mold.

shown in Fig.4 and hasthe axia1 grooves; 24in the side walls andtopfacethereof, .whi'chform the reinforcing ribs I 9, and thecircumferential groove fi which formsthe annularrib f8; The core has theprint The apparatus for molding or forming the-core w, 'partlyxinsection,

2 6 for locating the amin to imprint the adjacent end face of the coreby openings receiving a core 33 to provide the wrist pn bosses ll of thepiston. The diameter of the cavity 29 is reduced at the upper endthereof, as indicated at 34 to provide the core portion 35.

which in turn forms that portion of the piston having the grooves H5.

The wall of each part 27, 28' bounding thev cavity 29 has a plurality ofgrooves 36 therein extending axially with respect to the cavity 29. Avane or finger 21 is slidably received in each groove 36, and projectsinto the cavity 2-3 to form 'a. groove in the side Wall and end face ofthe core. The parts. 21, 28 are provided with a pair of locating rods38. The core box is vented as at 29'.

The mold cavityv 29 has a print end 39, forming the core print 26, and:an axially opposite. end provided with a cover 6.0. having spaced slots.ll therethrough respectively registering with the grooves 36 forreceiving a vane or. finger 35. It

will be noted that the end portion of each vane drawn from the cavity 29and through the cover M3 by relatively moving the plate M- and vanes 31relative to the parts 21, 28 in a, direction axially with respect to thecavity 291, While. the parts 21, 28 are relatively separable in adirection transverse to. the cavity.

In making the core by the sandblasting method it was found, that by thusintroducing the mold forming sandinto the cavity 29 through the printend Bathe. sand became lodged between thevanes and their groove walls,and particularly so at the cover 40 and after a small number-of'coreswere, blown this sand acted as a wedge to prevent drawing of the vanes.It was foundthis .difiiculty could be overcome and the benefits of thesand-blasting method availed of by introducing the core forming sandthrough thecovered end ofthe core, it being understood that the printend 39 rested upon a suitable support (not shown). to retain the sandin, the cavity.

For theforegoing purpose the, cover 401's provided with'a blow hole 44receiving a sand conducting conduit lll The latter and the plate 4! are.movable by an; operating member ill, The Wal bo ndns the o en g 4 p ovded With an annular pointed rib-41 controlling. the height of th core frmi g and and pro de a Sharp and distinct portion at the adjacentportion of forming a depression therein. This constitutes a squeezingoperation by which the sand adjacent the blow opening is packed, thecover remaining in place to otherwise prevent interruption of thecontour of the end face during the squeezing or packing operation. Thedepression thus formed in the core provides the central piston boss 22.The tool $8 is then removed and the remaining parts 43, 21 and 23relatively separated. The piston is then cast by placing the core in asuitable mold as illustrated in Fig. 4. It will be understood that thevanes 3'! can be separated by moving the core box forming parts 21, 28while the vanes are stationary or N that the latter parts can remainstationary and the vanes moved. In either instance the vanes passthrough the covered end of the cavity. The invention also contemplatesthat means other than the operating member 26 can, be utilized inconjunction with the apparatus for drawing the'vanes. I

Although but one embodiment, of the invention is herein shown anddescribed, it will be understood that various changes in the size, shapeand arrangement of parts may be madev without departing from the spiritof my invention and it is not my intention to limit said invention otherthan by the terms of the appended claims.

I claim:

1. The method of forming a core in a core box having a print end, whichcomprisesmoving a cover and vanes axially into closing and insertedrelationship respectively with respect to theend hcicoret F s- '8 th vavt 5, s w

ia v d. t e n unde t od; h t. the. a y fi df o term. the o a llustr t dby the dot-t inest e l n o t e-c v y, 5 the vanes. are withdr w rom e. cv h o the cover member 40 and a suitable tool 48 having an end defininga portion of a sphere is-inserted through the blow hole d5 of; the cover#30 of the mold cavity opposite to said print end, filling said moldcavity from the end. thereof opposite to said; print end by introducinga blast of sand through said cover into said cavity, and producingrelative movement betweensaid vanes and; core box to thereby withdrawsaid vanes from saidcavity a direction axially with respect to the.cavity, I

2;. The method of forming a core in a core box having a print end, whichcomprises; moving a cover and vanes axially into, closing and insertedrelationship respectively with; respect to the end of the mold cavityopposite to said print end, filling said mold cavity from the endthereof opposite to said print end by introducing a blast of sand.through said. cover into said: cavity, producing relative movementbetween said vanes and core box to thereby withdraw said vanes from saidcavityin a direction axially with respect to, the cavity, and moving atool through said cover while the latter is engaged with the core toimprint the end face of the COIIG adjacent said cover. I

3. Themethod-o-f forming a core in a core box nc udin a mold a ty, aprint end and a cover at the end of the. cavity opposite the print end,which comprises projecting vanes. through said coverinto said cavity,admitting a blast of coreforming sand through said cover into saidcavity, and withdrawing saidvanes from saidcover and said. cavity byrelative separation thereof-in adirection axially withrespectto thecavity.

4. The method of forming a corein a; core box including a mold cavity, aprint end and. a cover at the end of the cavityopposite the print end,which comprises projecting vanes through. said cover into said cavity,admitting a blastof coreforming sand through said cover into saidcavity,withdrawing saidvanesfrom said cover and. said cavitybyrelativelseparation thereof; in a direction axially withrespe'ct tothe cavity, and insertin a directiontransverse to the core.

I ing, a tool through said cover while the latter is engaged with thecore to imprint the end face of the core adjacent thecover.

x 5. The method of forming a core in a core box,-

including a mold, cavity, a print end, a removable cover for the endofthe cavity opposite the i print end, and adraw member having vanesextending through the cover into the mold cavity, which comprises,introducing core-forming sand under pressure through said cover intosaid cavity, and producing relative movement between said draw memberand said core box in a direction axially with; respect to the moldcavity to thereby withdraw saidfvanes from said cavity through saidcover. Y

6 The method offforming a core in a core box said registering slots andhaving portions thereof respectively projecting from said cover'andwalls into-said cavity, and a draw plate overlying said cover secured tosaid vanes, said cover and said plate having registering openings foradmitting,

a blast of sand in an axial direction into said cavity, said plate andsaid vanes being relatively separable from said cover, core box and thecore in an axial direction with respect to said cavity.

10. Apparatus for forming a sandcore by sand blasting, comprising, acore box having a sandreceiving cavity and a print end, said boxincludingparts relatively separable in a direction transverse to saidcavity, cover means for the end of including a mold cavity, a print end,a removable cover for the end of the cavity opposite the print end, anda draw member having vanes extending through the cover into the moldcavity, which comprises, introducing core-forming sand under pressurethrough said cover into said cavity, pro- 1 ducing relative movementbetween .said draw member and said core box in a direction axially withrespect to the mold cavi'ty to thereby withdraw said vanes from saidcavity through-said cover, moving a tool through said cover while thelatter is engagedwith the core to imprint the end face of the coreadjacent said cover, and 7 removing said cover.

7. In a method for forming a core in a core box including relativelyseparable parts forming a ,moldcavity having a printend, a removablecover for the cavity opposite the print end and" vane removablyextending through said cover-'- 'into'fsaid cavitypwhich comprises,introducing a blast ofrcore-forming sand through said cover into saidcavity, relatively moving said vanes and mold cavity forming partstothereby withdra w said vanes from said cavity through said cover,

inserting a tool through said cover while the latter is engaged withth'ecore to imprintthe end face of the core adjacent said cover, removingsaid cover, and relatively separating said parts to said core in adirection axially with respectto thecavity for withdrawing said vanesfrom said 8. The method of forming a core in' amold cavity including aprint endand an opposite covered end having a blow hole, which comprisesmoving vanes into said cavity through the covered end thereof,introducingcore-formingsand under pressure intolsaid cavity through saidblow hole, withdrawing, said vane fromsaid cavity,

andpacking the core-forming sand adjacent the blow hole by a totalinserted through said blow 9. In an apparatus for molding a piston-formiing core having surface grooves, a core box having a cavity andcomprising, parts relatively separable only in a direction transverse tothe cavity, each of said parts having a slot in the wall thereofbounding thei'cavity and extending axially with respect to the latter, acover for one end of said cavity havingslots therethrough respectivelyregistering with theflrst mentioned slots, grooveformingvanes-respectively slidably received in 1 said box opposite said printend including a first member having slots extending therethrough and asecond member movable relative to thefirst member, vanes carried by saidsecond member f respectively extending through the slots in said 7 firstmember and projecting into said cavity, said:

members having an inlet opening therethrough l for admitting a blasto-f*sand axially into said:

cavity, said second member and saidpartsjbeing relatively movable in anaxial direction with respect to said cavity for withdrawing said vanesfrom said first member and said cavity, and a die w member insertablethrough the opening in said member for imprinting the adjacent endfaceofthe core. 1

11 Apparatus for forming a sand core by sand blasting, comprising, acore box having a sandreceivingcavity, said box includin partsrelatively, separable in a direction transverse to, said cavity,.each ofsaid parts having a vane-receiving slot in thatface thereof boundingsaid cavity and extending axially with respect to the latter, a drawplate associated .with one end of said cavity, vanes carried bysaidplate and respectively slidably disposed in said slots, said plat havingan opening thereinjfor admitting a blast of sand into said cavity -in adirection axially thereof,

said plate and said vanes being movable relative cavity.

12. Apparatus for forming a sand core by sand blasting comprising a corebox having a sandreceiving cavity, said box including parts relativelyseparable in a direction transverse to said cavity, each of said partshaving a vane-receiving slot in that face thereof boundingsaid cavityand extending axially with respect to the latter, a

' cover for .said cavity having slots therethrough adapted toregisterwith the respective slots of said cavity, a draw plate extendingover said cover, vanes carried by said draw plateand respectivelyslidably disposed in said registering slots, said cover and said drawplate having registering openings therein for admitting a blast of sandinto said cavity, said draw plate and said vanes being movable relativeto said parts in a direction axially with respect to said cavity forwithdrawing said vanes from the latter.

EDGAR A. PETERSEN. j

